In the computer industry, databases are used for an array of purposes ranging from credit card billing to network maintenance. Databases help make worldwide commerce possible (including e-commerce) as well as allow for massive amount of record keeping and record storage. Many databases rely on servers for general operation. Databases function in conjunction with computer code often written in database specific languages.
Structured Query Language (SQL) is a programming language commonly used in databases with several variations available. There are proprietary versions of SQL; for example, Transact-SQL is a specific proprietary version of SQL. In many instances, SQL operates on databases implementing relational database management systems (RDBMS). This bases a database model on first order logic as well as representation of objects. SQL servers can also function as object-orientated databases. Other database languages exist besides SQL including XQuery, which can be used for various functions such as extracting information from a database.
Databases are designed to process multiple concurrent requests. For example, multiple people can make a credit card purchase at the same time over the Internet. A central database server can record each one of these transactions at the same time with each transaction requiring a specific amount of server resources. In addition, each transaction can require different amount of resources to complete a successful operation and a database server can provide those resources. Moreover, a database server can handle a multitude of different requests all at the same time. For example, one user can be making a purchase with a credit card while another user signs up for a new account. Both operations require use of the same resource, system memory.